The present invention relates to a metrological instrument for measuring one or more surface characteristics such as form, for example roundness, and/or roughness or surface texture.
An example of such a metrological instrument is the SURTRONIC 10 manufactured by Taylor Hobson Limited, of Leicester, England, UK. The SURTRONIC 10 is a pocket-sized device which can be used on the shop floor for in-situ measurement of surface texture. The user simply places the SURTRONIC 10 on the surface to be measured and, at the press of a button, a single number which is indicative of the surface characteristic being measured is displayed.
When the SURTRONIC 10 is placed on a workpiece surface whose texture is to be measured and is then activated, the tip of a stylus is traversed along a measurement path across the surface. The stylus is pivotally mounted so as to enable the stylus tip to follow changes in the surface due to its texture or roughness. The stylus is connected to a piezoelectric transducer which generates charges in response to the pivotal movement of the stylus. The charges generated by the piezoelectric transducer are processed to provide a measurement of the surface roughness or texture which is displayed on a screen.
The SURTRONIC 10 has found wide applicability for the measurement of surface characteristics. However, the Surtronic 10 can be difficult to use where the surface to be measured is difficult for the user to access. Also, protection of the stylus tip from damage when not in use can be a problem and requires the provision of a special sliding gate which has to be manually opened for measurement and closed for storage.
In one aspect, the present invention provides a metrological instrument having a measurement unit arranged to communicate remotely without physical connection to a user-interface unit.
According to one aspect of the present invention, there is provided a metrological instrument comprising the measuring unit and a user-interface unit, the measuring unit and the user-interface unit being separable and being arranged to communicate with one another remotely without any physical connection therebetween, at least when the units are separated. The user interface may comprise at least one of a display and a control unit operable by a user. The remote link may be an infra-red link.
According to one aspect of the present invention, there is provided a metrological instrument comprising a measurement unit and a further unit with the units being arranged to be coupled together in a first configuration in which the measurement unit is allowed to carry out a measurement and in a second configuration in which the measurement unit is protected or covered by the further unit. Preferably, the further unit comprises a user interface unit which may comprise at least one of the display and a control unit for the instrument.
According to one aspect of the present invention, there is provided a metrological instrument comprising: a measurement unit having a pivotally mounted stylus carrying a stylus tip for traversing a surface to be measured, means for traversing the stylus tip along a traverse path across the surface tip in measured and a transducer for providing a signal indicative of pivotal movement of the stylus as the stylus tip traverses the surface; and a user-interface unit for providing a user with a result representative of a characteristic of the surface being measured and derived from the transducer signal, the measurement and user-interface units being separable and being arranged to be coupled together in a first configuration in which the measurement unit is allowed to carry out a measurement and a second configuration in which the stylus tip is protected by the user-interface unit.
In another aspect, the present invention provides a measurement unit for a metrological instrument, the measurement unit having means for communicating remotely, for example by infra-red radiation, with a user-interface unit of the instrument.
In another aspect, the present invention provides a user interface unit for a metrological instrument, the user interface unit having means for communicating remotely, for example by infra-red radiation, with a measurement unit of the metrological instrument.
In another aspect, the present invention provides a measurement unit for a metrological instrument, the measurement unit being arranged to be coupled to a user interface unit of the metrological instrument in at least two different configurations with the measurement unit being capable of carrying out a measurement when the units are coupled in a first configuration and being protected against damage when the units are coupled in a second configuration.
In another aspect, the present invention provides a user-interface unit for a metrological instrument, the user-interface unit being connectable to a measurement unit in at least two different configurations with, in a first configuration, the measurement unit being allowed to carry out a measurement and in a second configuration the measurement unit being protected against damage by the user-interface unit.
In a metrological instrument embodying invention, the ability to communicate remotely, that is without physical connection, to a user interface allows the measurement unit to be placed in location that would be difficult to access if the measurement unit was permanently connected to the user interface. Also, the fact that the remote communication is achieved without any physical link between the two units means that the user can reposition or handle the user interface unit after the measurement unit has been placed at the desired measurement location without effecting the position of the measurement unit.
According to one aspect of the present invention, there is provided a metrological instrument for measuring a characteristic of a surface of a workpiece, said metrological instrument having a control unit and a traverse unit, said control unit comprising a user interface and said traverse unit comprising means for generating a signal representative of the characteristic of the surface, wherein the control unit and the traverse unit are adapted such that a signal from the control unit can initiate the measurement of the surface characteristic by the traverse unit by remote control. By establishing a remote control link between the traverse unit and the control unit, once the control unit has been placed on the surface to be measured, the user can initiate a measurement as and when desired without needing to directly access the traverse unit.
The terms xe2x80x9cremote communicationxe2x80x9d and xe2x80x9cremote controlxe2x80x9d as used above cover the case where signals are transmitted between the user interface or control unit and measurement or traverse unit without a physical link between the unit, that is there is no wire, optical fibre or the like physically connecting the control unit to the traverse unit. This means that the user can move or adjust the control unit without affecting the positioning of the traverse unit.
In an embodiment, said control unit and said traverse unit comprise infra-red transmission and reception circuitry to provide the remote link. The use of infrared rather than radio (RF) transmission is advantageous because of the lower cost and lower susceptibility to interference.
In an embodiment, said user-interface or control unit and said measurement or traverse unit both include an integrated circuit comprising modulation circuitry, transmitter driver circuitry and a transmitter to provide transmission circuitry and a receiver and demodulator to provide reception circuitry, thereby reducing size and, in the case of mass production particularly, cost.
In an embodiment, the measurement or traverse unit has a plurality of receivers are located at different positions on the measurement or traverse unit for communicating with the control or user-interface unit. This enables communication still to occur even if one of the receivers is obscured for some reason. The use of a plurality of receivers is particularly advantageous where communication is effected optically, for example using infra-red radiation, because it improves the possibility of a line-of-sight between a transmitter and receiver being available even if the traverse or measurement unit is positioned in a confined location.
In one aspect of the present invention there is provided a metrological instrument comprising a control unit including a first connection means and a measurement or traverse unit including a second connection means for coupling with the first connection means, the traverse and control unit having data communication means arranged to enable remote communication between the units when the units are separated from one another, the data communication means being arranged such that when the control unit and the measurement or traverse unit are connected via the first and second connection means the data communication means of the control unit is adjacent to the data communication means of the traverse unit. This enables communication between the units to take place in the same manner and using the same communication means when the units are connected together and when the units are separate from one another.
In an embodiment, the traverse or measurement unit comprises a third connection means arranged so that the control unit is connectable to the measurement traverse unit via the first and third connection means such that the measurement or traverse unit is protected by body of the control unit. In an embodiment, the body of the control unit protects a stylus tip of the measurement or traverse unit when the two units are connected via the first and third connection means.
According to one aspect of the present invention, there is provided a metrological instrument for measuring a characteristic of a surface of a workpiece by moving a stylus tip over the surface to be measured, said metrological instrument having a control unit and a traverse unit, said control unit comprising a user interface and a first connector and said traverse unit comprising a stylus arm for holding the stylus tip, means for generating a signal representative of the characteristic of the surface in response to movement of the stylus tip over the surface and a second connector, the control unit and the traverse unit being adapted such that a signal from the control unit can initiate the measurement of the surface characteristic by the traverse unit, wherein the first connector is arranged to engage the second connector to connect the control unit and the traverse unit such that the body of the control unit protects the stylus tip when the apparatus is not in use.